An Update on Arsenic Green: When the World was Dying for Color

By Lidia Plaza

In my second blog post of the summer, I discussed the copper arsenic green pigments that I suspected had been used to color at least a few of the garments in the MdHS collection. Since then I've done a lot more research and finally tested those garments for traces of arsenic. On Wednesday August 12, I revealed my findings to the museum and the community at the Intern presentations.

The Colorful 19th Century?

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Today, when we think of the 19th century, the images that might come to mind are black and white photographs–drab, dreary images of stiff, posed people wearing fussy clothes. Perhaps we think of Queen Victoria, the somber woman in perpetual mourning for her beloved husband Albert, or maybe we think of war heroes dressed in solemn uniforms. In any case, “colorful,” is probably not the adjective that immediately springs to mind, but it should be, for I argue that the 19th century witnessed the last golden age for color. Though the 19th century began rather plainly, as neoclassical and empire fashions called for crisp whites and pale colors, the public's love of colorful clothes was soon revived. Before the century was over, textile dyers would find help from merchants, diplomats, and chemists, who were willing to risk their fortunes, reputations, and even their lives, all in the quest for color.

If you are skeptical that colorful is an appropriate adjective for 19th century clothing, I can only offer the MdHS historic clothing collection as proof.

Impressed by these vibrant clothes, I began investigating the history of textile dyes. I found many exciting stories about the extreme lengths people once went to in order to have colorful clothes, but since the beginning of this internship I was particularly captivated by the story of the copper arsenic greens that remained popular even as they destroyed the health of those that used it. Why, I wondered, were people so crazy for color?

The Craze for Color

It’s difficult for us today to appreciate how important, how valued color used to be. Today we can see any color we want. We can open up a computer and pull up any hue we can imagine. We can walk into a store and buy a shirt in any shade we desire. People living before the 1850’s didn’t live in such a world. For millennia mankind struggled to perfect and protect the magic of color. In the ruins of Pompeii, archaeologists discovered perfectly preserved dye houses with pots of dye still intact, for even then the business of dying textiles was already an ancient industry.[1] Centuries later, medieval dye masters organized themselves into elite, secretive guilds, slowly learning to harness the full potential of the available dyestuffs like woad and red mater. Meanwhile, the Aztec empire bankrolled itself on the trade of cochineal, which the ancient people of Mexico had spent centuries domesticating.[2]

But for all of the centuries of work, no one had yet truly mastered color. Many natural dyes produced colors that were muted and dull. Dyes would fade with sun exposure and with washing. With some dyes requiring as many as 13 separate steps to produce, the dyer could ruin the color with the slightest mistake.[3] As a result, brilliantly dyed fabric was highly prized. Many people either could not afford it, or were forbidden from wearing it due to strict sumptuary laws, which limited the use of certain colors to those of a certain social rank.[4] Those of a certain social rank, however, were willing to pay whatever it cost to have the most exquisitely colored clothes. To keep their customers coming, the dyers of Europe were always desperate to find a new edge on their craft–the next exotic color, the next innovative technique. Glamorous, mysterious colors trickled into Europe from the East, but in 1492, Columbus sailed the ocean blue and Europe found a whole new world of dyestuffs. In the following centuries, the business of trading dyes exploded into an international, transcontinental industry of which the risks were as high as the rewards. Pirates and privateers roamed the waters outside of major ports preying merchant ships carrying dyes. Government officials sent spies overseas to steal the secrets of foreign dye experts.[5] In a world before easily synthesized color, there was actual gold at the end of the rainbow.

Color Meets Chemistry

Though it wasn't obvious at the turn of the 19th century, the future of dyeing innovations lay not in a foreign harbor, but in a local test tube. Dyeing in the previous century had really been an art, not a science, and there was little indication that the 19th century would be any different. Dyers tended to rely on their instincts and their experience rather than on scientific method. “Few of our dyers are chemists, and few chemists dyers,”[6] William Henry, a Manchester chemist, complained in 1781. That would soon change, however, for even as William Henry wrote those words, chemists and dyers were already learning the value of each other’s trade.

In 1775, Carl Wilhelm Scheele was experimenting with arsenic and discovered that he could produce a green pigment out of copper arsenites. Twenty five years later, emerald green, or copper acetoarsenite 3Cu(ASO2)2.Cu(CH3COO)2, was introduced as an improvement on the original Scheele’s green.[7] These copper arsenic greens were technically pigments, not dyes, but they were used to color fabrics. More commonly, they were used in paints, wallpapers, and even in coatings for candy.

However, arsenic, if you don’t know, is a potent poison. Arsenic alone is a carcinogen, but arsenic is most deadly as either arsine gas (AsH3), arsenite (AsO33-), or arseate (AsO43-).[8] Arsenic poisoning causes basic cellular failure, and victims can suffer from symptoms including: vomiting, diarrhea, hemorrhagic gastritis, pulmonary edema, hypotension, delirium, shock, convulsions, and eventually death.[9] Overtime, alarming stories started to circulate telling of children dying from the green wallpaper in their nurseries and from the green carpets on the floors where they played.[10] There were rumors that Napoleon was done in, not by stomach cancer, but by the green walls at Longwood Manor in St. Helena where he died.[11]

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Doctors began warning the public to stay away from the copper arsenic pigments, and many promptly got rid of their green décor. Queen Victoria famously had the green wallpapers removed from Buckingham Palace after a foreign dignitary complained they made him sick.[12] Even Scheele, as he was rushing to the patent office with his new pigment recipe, was aware of the dangerous health risks his invention posed. Yet the color was still in use into the 20th century. The question is, why? One problem was a lack of definitive evidence that it was indeed the copper arsenic pigment, and not something else, like the lead pipes in everyone’s plumbing, that caused these deaths. Yet the real problem was that many people still liked the color. As Dr. Thudichum indelicately put it in a meeting for the Society of Arts in London, the alternatives to using arsenic colors were “abominable grays, hideous browns, and dreadful yellows.”[13] The quest for color was still very much alive in the 19th century and even the risk of poisoning didn’t discourage the hunt.

Green Before Chemistry

One might assume that because green is such an abundant color in nature that there must be an abundance of natural green dyes, but nothing could be further from the truth. Natural, true, green dyes are shockingly few and far between, and there are only few true green pigments. Those few pigments that exist are notoriously difficult to work with. When decorating Mount Vernon, George Washington personally chose verdigris green paint, which when first applied was a bright, pistachio color. Overtime, however, the green reacted with the lead white paint on the finishes of the room and turned dark. This problem was well known to the great masters, such as Leonardo da Vinci, who also complained that the pigment easily faded if not varnished over quickly.[14] There were a few other green pigments, but they had equally challenging quirks, and so it is easy to see how manufacturers like William Morris, the man most famous for selling arsenic-laced wallpaper, were willing to dismiss the pesky rumors about poisonings.[15]

Textile dyers may have been even more enthusiastic about this new green than painters and wallpaper makers. If painting a canvas green was challenging, dyeing a textile green was a true test of the dyer’s skill. Red dyes could be made with red madder or with Kermes, imported from modern-day Iran, but those with deep enough pockets might prefer cochineal for the most brilliant reds. Turmeric from western Asia could produce lovely yellows, though dyer’s weld was more common in early Europe. Wild indigo and woad both produced beautiful blues. Even purple dye could be made from sea snails, though the secrets of that process were essentially lost in the fall of Constantinople.[16] But green, green was a problem. For centuries, that problem was often solved by first dying the fabric yellow and then over-dying it with blue. It was an imperfect solution. Dyers had to do twice the work twice as well, for the smallest mistake in either process would ruin the final result. Achieving a consistent color through multiple batches was a true feat and the resulting fabric was worth a pretty penny. Those who could afford such fabric were out to make a statement. Robin Hood and his merry men did not dress in green for camouflage, quite the opposite; they wore green to throw their stolen wealth in the faces of the Nottingham nobles they stole from.[17] Desperate to find a better way to dye fabric green, some textiles dyers turned to the arsenic pigments to color their fabrics. Naturally I was curious if any of the fabrics we were processing here at MdHS were dyed this way.

Testing for Arsenic in the MdHS Costume Collection

As soon as I started investigating the chemistry of green dyes, I found myself puzzling over literature that neither my introductory textile science course, nor my courses in organic chemistry truly prepared me for. Turns out dyeing fabrics really is as hard as they say. What makes dyes so complicated is that unlike pigments, which adhere to the surface of an object with binders, dyes are chemically bonded to the dyed material. Different kinds of dyes bond in different ways to produce different results. Direct dyes bond to fabrics with ionic bonds, while indirect dyes use an intermediate component, called the mordant, to act as a bridge in forming an ionic bond to the textile. Vat dyes do not technically bond chemically with the textile, but rather the dye becomes trapped inside the textile fibers and, in practice, has a similar result. Sometimes figuring out which process was used to dye the textile can help identify the dye. Unfortunately, none of the tests I read about were really applicable to copper arsenic pigments, so I decided that testing directly for arsenic was probably my best bet at chemical identification.

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This summer we’ve come across a number of green items, but, of course, not all of them were dyed with an arsenic green. This bodice was obviously dyed with a yellow and blue over-dye technique because the two dyes are separating in certain spots. This bodice was understandably not a great candidate for an arsenic green dye.

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Ultimately I choose 4 items that had the right sort green to test for arsenic content. I got my hands on two arsenic testing kits and decided to try them both. One was newer, but of lower quality, the other was higher quality but older. Though they used slightly different reagents, they were very similar procedurally. For both tests I swabbed the test subjects with a damp cotton swab and then soaked the swab in distilled water and tested the water for arsenic.

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All of the garments I tested had under 0.01g/ml of arsenic, which is to say none. However, that doesn’t mean that these bodices weren’t dyed with an arsenic-based colorant; all that means is that almost no arsenic transferred to the swab and reacted with the tests' reagents. This type of chemical testing is very non-invasive, but, as a result, it’s also non-conclusive. Microscopic analysis could definitively determine how these garments were dyed.[18]

The Gift of Green Dye

If these bodices were not dyed with arsenic green, however, that would not be entirely surprising. Arsenic-based greens remained popular in paints, but dyers soon found better alternatives. In 1842 China lost Hong Kong to Britain, and in 1845 French officials visited the newly British port to see what they could find for themselves. The grand prize of their spoils might not have seemed impressive at a first glance–just a little cake of green mud–but they had stumbled upon the holy grail of the dye industry: a true, colorfast, natural green dye. It was called Lo Kao, and it came from what can only be described as the giving tree for dyers. The dye came from the bark of the Buckthorn tree, the leaves of which could produce yellow dyes and the berries of which could be made into a low-quality green watercolor. These later two properties of the Buckthorn tree were more familiar to the Europeans, but the process of stripping the bark and making it into the magical green dye, however, was new.[19]

Ironically, almost as soon as Lo Kao became widely available, it was abandoned. It had been over 80 years since the discovery of Scheele’s green, and in that time chemists had learned to be dyers, as dyers had become chemists. While the French were sailing to Hong Kong, at home in France, Guinon began producing the very first synthetic dye. This dye was yellow picric acid, and it was a new type of dye known as a coal-tar dye.[20] Meanwhile, Queen Victoria’s prince consort, Albert, was eager to bring German scientific excellence to Britain, and to that end he founded the London’s Royal College of Chemistry. Unlike many institutes at the time, the London offered extensive laboratory training, which drew fifteen-year-old William Perkins to its doors in 1853.[21] Three short years later, Perkins famously discovered aniline purple, more commonly called mauve.[22] The dye was a fabulous success, and other academic chemists immediately started their own experiments with chemical dyes in hopes of replicating Perkins’ financial success. In 1866, iodine green emerged on the market as one of the first synthetic green dyes.[23]

Victims of the Coal Tar Dyes

Perkins’ mauve was so popular, it was joked that there was an epidemic of “mauve measles,”[24] but the joke was not far from the truth. Like Sheele's green, the coal-tar dyes posed serious health risks. Poorly finished synthetic dyes leached out of fabrics causing mild to sever skin irritations.[25] In the factories that made coal-tar dyes, workers were exposed to deadly chemical such as toluene, aniline, and dinitrobenzene, just to name a few.[26] Perkins' dye came from experiments with naphthalene and naphthalidine, very dangerous chemicals if handled incorrectly.[27] One of Perkins’ own classmates burned to death in an industrial accident while trying to make a commercial chemical venture of his own. In addition, many synthetic dyes used arsenic in their processing.[28] After the fabric was dyed, the toxic dye baths were often just dumped into the surrounding lakes and rivers.[29] It seemed that the western world had jumped out of the arsenic green pot and into a coal-tar fire.

There was another way the coal-tar dyes posed a risk, however. Despite having its beginnings in England, synthetic dyes quickly became a German game due to favorable patent laws and a superior scientific infrastructure. At first, this was simply an annoyance to other nations, but with the outbreak of World War I, it became a problem of national security. German dye chemists had spent decades learning the ins and outs of the deadly compounds that produced their dyes. Now they would turn that knowledge towards the production of chemical weapons. The Allied forces scrambled to catch up, and by the end of the war most of the allied nations had thriving chemical industries of their own. When the war was over, many chemical weapons manufacturers turned back into dyers.[30] Before long, those chemists would realize the dream that mankind had failed to achieve for 6 millennia; they would master color, or at least they would come very close to it. Once there had only been a few dozen known dyes, but suddenly there were thousands.[31]

The End of the Rainbow

Unfortunately, almost no one noticed. Flashy, bright colors, it had been decided, were gaudy when used in excess, and the 19th century concluded almost as plainly as it had begun. The nail in the coffin of color came in the 1920’s when Coco Chanel popularized the little black dress, a staple of fashion to this day.[31] Never again would color captivate the public’s imagination the way it once had. And, of course, it couldn’t. Chemistry had reached into the sky and brought the rainbow down the earth for everyone to enjoy, but if there is one rule in fashion it is that everyone can have it, than no one wants it. So was it all for nothing? Well, that is one way to look at it. But I like to think that even if these colors don’t captivate us the way they once did, the story of how people were once so desperate for color that they wore arsenic is still a captivating tale.

[20] Hornix, Willem J. ”From Process to Plant: Innovation in the Early Artificial Dye Industry.” The British Journal for the History of Science, Vol. 25, No. 1, Organic Chemistry and High Technology, 1850-1950 (Mar., 1992), p.66.

[24] David, Alison Matthews and Elizabeth Seemelhack. Fashion Victims: The Pleasures and Perils of Dress in the 19th Century; Catalogue of an exhibition held at the Bata Shoe Museum in Toronto June, 18 2014-June 2016, p.18.